A motor generally corresponding to this description is to be found mentioned in various prior art publications, for instance in the U.S. Pat. No. 4,361,790 in which will be found described an electromagnetic motor having two rotation senses and which includes a magnetic circuit having two windings simultaneously energized. This arrangement essentially provides a stator exhibiting three polar expansions surrounding the rotor, one of which is common to two windings, the other two being respectively dependent on each of said windings. By the principle of flux conservation it follows that such an arrangement exerts an attractive force on the rotor directed towards the common polar expansion which is twice as high as the force which is exerted towards the two other polar expansions. From this it may be reasonably concluded that this one-sided magnetic attraction by the mechanical imbalance which it brings about will cause stresses on the motor bearings and axis so as to provoke wear, shortening the life of the motor.